Air conditioning system and control method thereof

Abstract

The invention relates to the technical field of air conditioners, particularly provides an air conditioning system and a control method thereof, and aims to solve the problem that an existing liquid homogenizer cannot realize accurate adjustment. In order to achieve the purpose, the control method of the air conditioning system comprises the following steps that the opening degree of the liquid homogenizer is determined according to working parameters of the air conditioning system; the method specifically comprises the steps that the target exhaust superheat degree of the air conditioning system is determined according to target working parameters of the air conditioning system; according to the actual working parameters of the air conditioning system, the current exhaust superheat degree of the air conditioning system is determined; and according to the target exhaust superheat degree and the current exhaust superheat degree, the adjusting amount of the liquid homogenizer is determined. The method is specifically obtained according to an increment PID algorithm, the adjusting quantity calculated by the adjusting quantity can be more accurate, then it is guaranteed that the liquid homogenizer is properly adjusted every time, and the evaporator works in a better state.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and specifically provides an air conditioning system and a control method thereof. Background Art

[0002] With the development of society and technology, air conditioners have become essential electrical appliances in families and offices. In offices or large families, in order to ensure the cooling and heating efficiency, central air conditioners are generally used.

[0003] The evaporators of central air conditioning units include dry type and flooded type, etc. The flooded evaporator has the advantages of simple processing, stable performance and high heat exchange efficiency, and is widely used.

[0004] However, the operating conditions of the air conditioning unit are complex in actual operation, and the state of the refrigerant in the gas-liquid mixed state in the liquid inlet pipe of the evaporator changes greatly, resulting in a large change in the flow velocity of the liquid through the holes of the liquid distributor, and further causing the uneven distribution of the refrigerant flow field in the evaporator under working conditions with large working parameters or high chilled water outlet temperature, etc., affecting the heat exchange efficiency, and even having the risk of liquid carry-over during suction. Serious liquid carry-over will affect the service life of the compressor and even cause alarm and shutdown.

[0005] In order to solve the above technical problems, a liquid distributor with adjustable aperture is provided in the evaporator, and the flow velocity of the refrigerant is adjusted by adjusting the opening degree of the liquid distributor; however, the existing opening degree adjustment method of the liquid distributor is relatively rough, unable to achieve precise adjustment, and unable to match the current operating conditions of the air conditioner, resulting in uneven distribution of the refrigerant flow field in the evaporator, affecting the heat exchange efficiency, and even having the risk of liquid carry-over during suction. Serious liquid carry-over will affect the service life of the compressor and even cause alarm and shutdown.

[0006] Therefore, there is an urgent need for an air conditioning system and a control method thereof to solve the above technical problems. Summary of the Invention

[0007] The present invention aims to solve the above technical problems, that is, to solve the problem that the existing liquid distributor cannot achieve precise adjustment, resulting in uneven distribution of the refrigerant flow field in the evaporator, affecting the heat exchange efficiency, and even having the risk of liquid carry-over during suction. Serious liquid carry-over will affect the service life of the compressor and even cause alarm and shutdown.

[0008] In a first aspect, the present invention provides a control method for an air conditioning system, the air conditioning system includes a liquid distributor, and the control method includes the following steps:

[0009] Determine the opening degree of the liquid distributor according to the working parameters of the air conditioning system.

[0010] In a specific embodiment of the control method of the above air conditioning system, "determine the opening degree of the liquid distributor according to the working parameters of the air conditioning system" includes:

[0011] Determine the target superheat of exhaust of the air conditioning system according to the target operating parameters of the air conditioning system;

[0012] Determine the current superheat of exhaust of the air conditioning system according to the actual operating parameters of the air conditioning system;

[0013] Determine the adjustment amount of the liquid distributor according to the target superheat of exhaust and the current superheat of exhaust. In the specific implementation manner of the control method of the above air conditioning system, "determine the adjustment amount of the liquid distributor according to the target superheat of exhaust and the current superheat of exhaust" includes:

[0014]

[0015] wherein, δU(K) is the single - time adjustment amount;

[0016] E(t) is the sampling deviation of this time, E(t)= current superheat of exhaust - target superheat of exhaust;

[0017] E(t - 1) is the sampling deviation of the last time;

[0018] E(t - 2) is the sampling deviation of the time before last;

[0019] Kp is the p value of the liquid distributor;

[0020] Ti is the i value of the liquid distributor;

[0021] Td is the d value of the liquid distributor;

[0022] Ts is the adjustment period of the liquid distributor;

[0023] a, b, c, d, f are constants.

[0024] In the specific implementation manner of the control method of the above air conditioning system, "determine the adjustment amount of the liquid distributor according to the target superheat of exhaust and the current superheat of exhaust" further includes:

[0025] If the current superheat of exhaust is within the range of the target superheat of exhaust ± superheat of exhaust dead zone, then the adjustment amount = 0.

[0026] In the specific implementation manner of the control method of the above air conditioning system, "determine the adjustment amount of the liquid distributor according to the target superheat of exhaust and the current superheat of exhaust" further includes:

[0027] When the absolute value of the single - time adjustment amount δU(K) is greater than the single - time maximum allowable adjustment amount, the liquid distributor is adjusted according to the single - time maximum allowable adjustment amount.

[0028] In the specific implementation of the control method of the above air-conditioning system, 6. The control method of the air-conditioning system according to claim 1, wherein "determining the opening degree of the liquid distributor according to the working parameters of the air-conditioning system" includes:

[0029] Determine the target liquid level of the evaporator according to the target working parameters of the air-conditioning system;

[0030] Determine the current liquid level of the evaporator according to the actual working parameters of the air-conditioning system;

[0031] Determine the adjustment amount of the liquid distributor according to the target liquid level and the current liquid level.

[0032] In the specific implementation of the control method of the above air-conditioning system, "determining the opening degree of the liquid distributor according to the working parameters of the air-conditioning system" includes:

[0033] Determine the target inlet and outlet water temperature difference liquid level of the evaporator according to the target working parameters of the air-conditioning system;

[0034] Determine the current inlet and outlet water temperature difference of the evaporator according to the actual working parameters of the air-conditioning system;

[0035] Determine the adjustment amount of the liquid distributor according to the target inlet and outlet water temperature difference and the current inlet and outlet water temperature difference.

[0036] In the specific implementation of the control method of the above air-conditioning system, "determining the opening degree of the liquid distributor according to the working parameters of the air-conditioning system" includes:

[0037] Determine the target pressure difference between the condenser and the evaporator according to the target working parameters of the air-conditioning system;

[0038] Determine the actual pressure difference between the condenser and the evaporator according to the actual working parameters of the air-conditioning system;

[0039] Determine the adjustment amount of the liquid distributor according to the target pressure difference and the current pressure difference.

[0040] In a second aspect, the present invention provides an air-conditioning system, which includes a liquid distributor and a control module, and the control module is configured to be capable of executing the control method of the air-conditioning system as described above.

[0041] In the specific implementation of the above air-conditioning system, the liquid distributor includes a substrate, an adjustment plate and a driving member;

[0042] A plurality of first liquid equalizing holes are provided on the substrate, and second liquid equalizing holes corresponding to the first liquid equalizing holes are provided on the adjusting plate. The adjusting plate is attached to and slidably arranged on the substrate. The driving member can drive the adjusting plate to move so as to adjust the area covered by the first liquid equalizing holes, and further adjust the passing area of the first liquid equalizing holes; and / or

[0043] One of the adjusting plate and the substrate is provided with a connecting post, and the other is provided with a sliding groove. The connecting post is arranged through the sliding groove.

[0044] In the case of adopting the above technical solution, the air-conditioning system of the present invention includes a liquid equalizer, and the control method includes the following steps:

[0045] According to the working parameters of the air-conditioning system, determine the opening degree of the liquid equalizer. Specifically, it includes: determining the target exhaust superheat degree of the air-conditioning system according to the target working parameters of the air-conditioning system; determining the current exhaust superheat degree of the air-conditioning system according to the actual working parameters of the air-conditioning system; and determining the adjustment amount of the liquid equalizer according to the target exhaust superheat degree and the current exhaust superheat degree. Specifically, it can be obtained according to the incremental PID algorithm, which can make the calculated adjustment amount more accurate, and then ensure that each adjustment of the liquid equalizer is appropriate, so that the evaporator works in a better state.

[0046] Furthermore, it can be ensured that when the volume of the gas-liquid mixed refrigerant entering the evaporator increases, the opening degree of the liquid equalizer will be increased, the effective aperture of the liquid equalizer will be increased, that is, the effective liquid passing area of the liquid equalizer will be increased, the flow rate of the refrigerant can be kept stable, the increase in the flow rate of the refrigerant can be avoided, and further the increase in the liquid level of the evaporator and the phenomenon of liquid carry-over during suction of the compressor can be avoided, thereby ensuring the service life and performance of the compressor.

[0047] It can also be ensured that when the volume of the gas-liquid mixed refrigerant entering the evaporator decreases, the opening degree of the liquid equalizer will be decreased, the effective liquid passing area of the liquid equalizer will be decreased, that is, the effective aperture will be decreased; the flow rate of the refrigerant can be kept stable, the too low flow rate of the refrigerant can be prevented, and the uneven distribution of the refrigerant in the liquid equalizer can be avoided. Furthermore, it can avoid the small amount of refrigerant far from the liquid inlet of the evaporator, poor heat exchange effect, and reduction of the heat exchange capacity of the evaporator caused by the uneven distribution of the refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings:

[0049] Figure 1 is a schematic structural diagram of the liquid equalizer provided in Embodiment 1 of the present invention;

[0050] Figure 2 is a main flowchart of the control method of the air-conditioning system provided in Embodiment 1 of the present invention;

[0051] Figure 3 It is a detailed step flowchart of step S2 in the first embodiment of the present invention;

[0052] Figure 4 It is a detailed step flowchart of the control method of the air conditioning system provided in the first embodiment of the present invention;

[0053] Figure 5 It is a detailed step flowchart of step S2 in the second embodiment of the present invention;

[0054] Figure 6 It is a detailed step flowchart of step S2 in the third embodiment of the present invention;

[0055] Figure 7 It is a detailed step flowchart of step S2 in the fourth embodiment of the present invention.

[0056] List of reference numerals:

[0057] 1. Substrate; 11. First liquid equalizing hole; 12. Connecting column; 2. Adjusting plate; 21. Second liquid equalizing hole; 22. Sliding groove; 3. Front driving member. Detailed implementation manners

[0058] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention.

[0059] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0060] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "setting", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0061] A liquid distributor with adjustable aperture is provided inside the evaporator, and the refrigerant flow rate is adjusted by adjusting the opening degree of the liquid distributor. However, the existing method for adjusting the opening degree of the liquid distributor is relatively rough, unable to achieve precise adjustment, and unable to match the current operating conditions of the air conditioner, resulting in uneven distribution of the refrigerant flow field inside the evaporator, affecting the heat exchange efficiency, and even having the risk of liquid carry - over during suction. Serious liquid carry - over will affect the service life of the compressor and even cause an alarm and shutdown.

[0062] To solve the above - mentioned technical problems, the present invention provides an air - conditioning system and its control method.

[0063] Embodiment 1

[0064] This embodiment discloses an air - conditioning system, which includes a control module, a compressor, an evaporator, a condenser, and an electronic expansion valve.

[0065] Among them, the compressor, the condenser, the electronic expansion valve, and the evaporator are arranged in sequence. The control module is configured to be able to execute the control method of the air - conditioning system; and is also able to control each module of the air - conditioning system to enable the air - conditioning system to operate normally.

[0066] Among them, the evaporator includes a liquid distributor; as Figure 1 shown, the liquid distributor includes a base plate 1, an adjusting plate 2, and a driving member. Among them, a plurality of first liquid - distributing holes 11 are provided on the base plate 1, and second liquid - distributing holes 21 corresponding to the first liquid - distributing holes 11 are provided on the adjusting plate 2. The adjusting plate 2 is attached to and slidably arranged on the base plate 1. The driving member can drive the adjusting plate 2 to move to adjust the area of the first liquid - distributing holes 11 covered by the adjusting plate 2, thereby adjusting the passing area of the first liquid - distributing holes 11, that is, adjusting the effective liquid - passing area of the liquid distributor. After the first liquid - distributing holes 11 and the second liquid - distributing holes 21 are completely aligned, the effective liquid - passing area of the liquid distributor is the largest; when the first liquid - distributing holes 11 are completely covered by the adjusting plate 2, the liquid distributor is completely closed and the medium cannot flow through.

[0067] Among them, the driving member is specifically a linear driving member, specifically an electric cylinder, etc.; its driving distance can be precisely controlled by the control module to precisely adjust the effective liquid - passing area of the liquid distributor. In other embodiments, the driving member can also be a servo motor cooperating with a lead - screw nut structure to realize driving the adjusting plate 2 to slide.

[0068] The adjusting plate 2 and the base plate 1, one of which is provided with a connecting post 12 and the other is provided with a sliding groove 22, and the connecting post 12 is arranged through the sliding groove 22; through this sliding arrangement, the adjusting plate 2 can stably slide relative to the base plate 1. Since the length of the liquid distributor is relatively long, a plurality of sliding connection parts can be arranged at intervals along the length direction, which can make the adjustment more stable. In addition, a plurality of driving parts can also be arranged at intervals, which can make the driving more stable, and further make the movement of the adjusting plate 2 more uniform and stable, thereby ensuring the accuracy of the adjustment of the liquid distributor. Regarding the sliding connection structure, it should be noted that although the connecting post 12 is matched with the sliding groove 22 in this embodiment, this is not a limitation of the present invention. On the premise of not deviating from the principle of the present invention, in other embodiments, the sliding block can also be arranged through a snap or mortise and tenon structure, and a sliding hole is arranged on the other. Or, a slide rail and a sliding groove are provided to realize the sliding connection between the two, which does not deviate from the basic principle of the present invention and will fall within the protection scope of the present invention.

[0069] As Figure 2 shown, the control method of the air conditioning system includes the following steps:

[0070] S1. Obtain the operating parameters of the air conditioning system;

[0071] S2. Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system.

[0072] Among them, step S2, "Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" specifically includes:

[0073] Specifically, as Figure 3 shown, "Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" specifically includes the following steps:

[0074] S21. Determine the target superheat degree of exhaust of the air conditioning system according to the target operating parameters of the air conditioning system; where the target operating parameters are specifically the parameters corresponding to the target operating conditions of the air conditioning system, specifically the theoretical values. The corresponding relationship between the target operating parameters and the target superheat degree of exhaust is a conventional selection in the art, and will not be elaborated in this embodiment. In addition, the target superheat degree of exhaust can specifically be a range value or a point value. In this embodiment, it is specifically a range value, but the intermediate value of the selected range value is used as the target superheat degree of exhaust to participate in the subsequent calculation.

[0075] S22. Determine the current exhaust superheat degree of the air conditioning system according to the actual working parameters of the air conditioning system. The actual working parameters include the exhaust temperature and exhaust pressure of the compressor. Obtaining the current exhaust superheat degree includes: detecting the exhaust temperature and exhaust pressure of the compressor, and calculating the current exhaust superheat degree according to the exhaust temperature and exhaust pressure. Among them, an exhaust temperature sensor is provided on the compressor, and the exhaust temperature is detected by the exhaust temperature sensor. An exhaust pressure sensor is also provided on the compressor, and the exhaust pressure is detected by the exhaust pressure sensor. The current exhaust superheat degree is calculated according to the exhaust temperature and exhaust pressure, and the specific calculation method is a conventional calculation method in the art, which will not be elaborated in the present invention.

[0076] S23. Determine the adjustment amount of the liquid distributor according to the target exhaust superheat degree and the current exhaust superheat degree.

[0077] Among them, step S23 "determine the adjustment amount of the liquid distributor according to the target exhaust superheat degree and the current exhaust superheat degree" specifically includes:

[0078] The adjustment amount is specifically obtained according to the incremental PID algorithm, and the specific calculation formula is as follows:

[0079]

[0080] Among them, δU(K) is the single adjustment amount;

[0081] E(t) is the deviation of the current sampling, E(t) = current exhaust superheat degree - target exhaust superheat degree.

[0082] E(t - 1) is the deviation of the previous sampling, that is, the difference between the current exhaust superheat degree and the target exhaust superheat degree of the previous sampling;

[0083] E(t - 2) is the deviation of the sampling before the previous sampling; that is, the difference between the current exhaust superheat degree and the target exhaust superheat degree of the sampling before the previous sampling;

[0084] Kp is the p value of the liquid distributor, that is, the P value of the PID algorithm; in this embodiment, it is 0.05, and in other embodiments, it can be determined according to the parameters and attributes of each module of the liquid distributor and the air conditioning system.

[0085] Ti is the i value of the liquid distributor, that is, the I value of the PID algorithm; in this embodiment, it is 100, and in other embodiments, it can be determined according to the parameters and attributes of each module of the liquid distributor and the air conditioning system.

[0086] Td is the d value of the liquid distributor, that is, the d value of the PID algorithm; in this embodiment, it is 50, and in other embodiments, it can be determined according to the parameters and attributes of each module of the liquid distributor and the air conditioning system.

[0087] Ts is the adjustment period of the liquid distributor; that is, it is the period Ts for each sampling and output of the adjustment amount.

[0088] a, b, c, d, and f are constants. In this embodiment, the values of a, b, c, and f are all 1; the value of d is 2. Regarding the values of a, b, c, d, and f, although they are 1 or 2 in this embodiment, this is not a limitation of the present invention. In other embodiments, the values of a, b, c, d, and f can also be other values. The specific values can be other values, and the values can be determined according to the parameters and attributes of each module of the liquid distributor and the air-conditioning system. This does not deviate from the basic principle of the present invention and will fall within the protection scope of the present invention.

[0089] If the current superheat degree of exhaust is within the range of the target superheat degree of exhaust ± the dead zone of the superheat degree of exhaust, the adjustment amount is zero. During the process of calculating the adjustment amount, the sampling deviation E(t) of this time is calculated first. If the sampling deviation of this time, -0.5 ≤ E(t) ≤ 0.5; then the adjustment amount is zero, that is, δU(K) = 0.

[0090] Step S23 "Determine the adjustment amount of the liquid distributor according to the target superheat degree of exhaust and the current superheat degree of exhaust" further includes:

[0091] When the absolute value of the single - time adjustment amount δU(K) is greater than the single - time maximum allowable adjustment amount, the liquid distributor is adjusted according to the single - time maximum allowable adjustment amount. That is, there is a limit to the single - time adjustment amount of the liquid distributor; in this embodiment, the single - time maximum allowable adjustment amount is 3%. Specifically, when the single - time adjustment amount is positive, the opening degree of the liquid distributor is increased according to the single - time maximum allowable adjustment amount, and when the single - time adjustment amount is negative, the opening degree of the liquid distributor is decreased according to the single - time maximum allowable adjustment amount.

[0092] In addition, the opening degree of the liquid distributor is adjusted between the maximum allowable opening degree and the minimum allowable opening degree. The maximum allowable opening degree is specifically the maximum opening degree of the liquid distributor, that is, 100%. In this embodiment, the minimum allowable opening degree is 45%; in other embodiments, it can also be other values. If the required opening degree of the liquid distributor is outside the allowable opening degree range, it means that other parameters need to be adjusted to solve the problem, and it is not appropriate to adjust the opening degree of the liquid distributor; an alarm needs to be given.

[0093] When the volume of the gas - liquid mixed refrigerant entering the evaporator increases, the adjustment amount is positive, that is, it is necessary to increase the opening degree of the liquid distributor, which can increase the effective aperture of the liquid distributor, that is, it can increase the effective liquid - passing area of the liquid distributor, keep the flow rate of the refrigerant stable, avoid the increase of the flow rate of the refrigerant, and further avoid the rise of the liquid level in the evaporator and the phenomenon of liquid carry - over during compressor suction, thereby ensuring the service life and performance of the compressor.

[0094] When the volume of the gas-liquid mixed refrigerant entering the evaporator decreases, the adjustment amount is negative. The performance requires reducing the opening degree of the liquid distributor, which can reduce the effective liquid passing area of the liquid distributor, that is, the effective aperture can be reduced; the flow rate of the refrigerant can be kept stable, preventing the flow rate of the refrigerant from being too low, and avoiding uneven distribution of the refrigerant in the liquid distributor. Furthermore, it can avoid the situation that the amount of refrigerant far from the liquid inlet of the evaporator is small due to uneven refrigerant distribution, resulting in poor heat exchange effect and reduced heat exchange capacity of the evaporator, etc.

[0095] As Figure 4 shown, the control method of the air-conditioning system includes the following detailed steps:

[0096] S01. Obtain the target operating parameters of the air-conditioning system;

[0097] S02. Determine the target exhaust superheat of the air-conditioning system according to the target operating parameters;

[0098] S03. Obtain the exhaust temperature and exhaust pressure of the compressor;

[0099] S04. Calculate the current exhaust superheat according to the exhaust pressure and exhaust temperature;

[0100] S05. Judge whether the current exhaust superheat is within the range of the target exhaust superheat ± exhaust superheat dead zone. If so, the adjustment amount is zero, that is, no adjustment is required. If not, go to step S07;

[0101] S07. Calculate the required single adjustment amount according to the incremental PID algorithm;

[0102] S08. Judge whether the absolute value of the single adjustment amount is greater than the single maximum allowable adjustment amount. If so, go to step S09; if not, go to step S10;

[0103] S09. Judge whether the opening degree of the liquid distributor after adjusting according to the single maximum allowable adjustment amount is between the maximum allowable opening degree and the minimum allowable opening degree. If so, adjust the opening degree of the liquid distributor according to the single maximum allowable adjustment amount; if not, give an alarm.

[0104] S10. Judge whether the opening degree of the liquid distributor after adjusting according to the single adjustment amount is between the maximum allowable opening degree and the minimum allowable opening degree. If so, adjust the opening degree of the liquid distributor according to the single adjustment amount; if not, give an alarm.

[0105] Embodiment 2

[0106] This embodiment discloses a control method of an air-conditioning system, which is basically the same as the control method in Embodiment 1, except for the parameters for determining the adjustment amount.

[0107] As Figure 5As shown in the figure, the step of "determining the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" specifically includes the following steps:

[0108] S021. Determine the target liquid level of the evaporator according to the target operating parameters of the air conditioning system; where the target operating parameters are specifically the parameters corresponding to the target operating conditions of the air conditioning system. The corresponding relationship between the target operating parameters and the target exhaust liquid level is a conventional selection in the art, and will not be elaborated in this embodiment. In addition, the target liquid level can specifically be a range value or a point value. In this embodiment, it is specifically a range value, but the intermediate value of the range value is selected as the target liquid level to participate in the subsequent calculations.

[0109] S022. Determine the current liquid level of the evaporator according to the actual operating parameters of the air conditioning system; the actual operating parameters specifically refer to the actual liquid level on the liquid side of the liquid level gauge.

[0110] S023. Determine the adjustment amount of the liquid distributor according to the target liquid level and the current liquid level. The adjustment amount is specifically obtained according to the incremental PID algorithm.

[0111] Embodiment 3

[0112] This embodiment discloses a control method for an air conditioning system, which is basically the same as the control method in Embodiment 1, except for the parameters for determining the adjustment amount.

[0113] As Figure 6 shown in the figure, the step of "determining the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" includes:

[0114] S031. Determine the target inlet and outlet water temperature difference liquid level of the evaporator according to the target operating parameters of the air conditioning system; where the target operating parameters are specifically the parameters corresponding to the target operating conditions of the air conditioning system. The corresponding relationship between the target operating parameters and the target inlet and outlet water temperature difference is a conventional selection in the art, and will not be elaborated in this embodiment. In addition, the target inlet and outlet water temperature difference can specifically be a range value or a point value. In this embodiment, it is specifically a range value, but the intermediate value of the range value is selected as the target inlet and outlet water temperature difference to participate in the subsequent calculations.

[0115] S032. Determine the current inlet and outlet water temperature difference of the evaporator according to the actual operating parameters of the air conditioning system; the actual operating parameters specifically include the current inlet water temperature and the current outlet water temperature of the evaporator; the current inlet and outlet water temperature difference is calculated according to the current inlet water temperature and the current outlet water temperature.

[0116] S033. Determine the adjustment amount of the liquid distributor according to the target inlet and outlet water temperature difference and the current inlet and outlet water temperature difference. The adjustment amount is specifically obtained according to the incremental PID algorithm.

[0117] Embodiment 4

[0118] This embodiment discloses a control method for an air conditioning system, which is basically the same as the control method in Embodiment 1, except for the parameters for determining the adjustment amount.

[0119] As Figure 7 shown, among which, "determining the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" includes:

[0120] S041. Determine the target pressure difference between the condenser and the evaporator according to the target operating parameters of the air conditioning system; where the target operating parameters are specifically the parameters corresponding to the target operating conditions of the air conditioning system. The corresponding relationship between the target operating parameters and the target pressure difference is a conventional selection in the art, and will not be elaborated in this embodiment. In addition, the target pressure difference can specifically be a range value or a point value. In this embodiment, it is specifically a range value, but the middle value of the range value is selected as the target pressure difference to participate in the subsequent calculations.

[0121] S042. Determine the actual pressure difference between the condenser and the evaporator according to the actual operating parameters of the air conditioning system; the actual operating parameters specifically include the current pressures of the evaporator and the condenser; the current temperature difference between the inlet and outlet water is calculated according to the current pressure of the condenser and the current pressure of the evaporator.

[0122] S043. Determine the adjustment amount of the liquid distributor according to the target pressure difference and the current pressure difference. The adjustment amount is specifically obtained according to the incremental PID algorithm.

[0123] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will all fall within the protection scope of the present invention.

Claims

1. A control method for an air conditioning system, characterized in that, The air conditioning system includes a liquid distributor, and the control method includes the following steps: Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system.

2. The control method of the air conditioning system according to claim 1, characterized in that, "Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" includes: Determine the target superheat degree of exhaust of the air conditioning system according to the target operating parameters of the air conditioning system; Determine the current superheat degree of exhaust of the air conditioning system according to the actual operating parameters of the air conditioning system; Determine the adjustment amount of the liquid distributor according to the target superheat degree of exhaust and the current superheat degree of exhaust.

3. The control method of the air conditioning system according to claim 2, characterized in that, "Determine the adjustment amount of the liquid distributor according to the target superheat degree of exhaust and the current superheat degree of exhaust" includes: Wherein, δU(K) is the single adjustment amount; E(t) is the sampling deviation of this time, E(t) = current superheat degree of exhaust - target superheat degree of exhaust; E(t - 1) is the sampling deviation of the last time; E(t - 2) is the sampling deviation of the time before last; Kp is the p value of the liquid distributor; Ti is the i value of the liquid distributor; Td is the d value of the liquid distributor; Ts is the adjustment period of the liquid distributor; a, b, c, d, f are constants.

4. The control method of the air conditioning system according to claim 3, characterized in that, "Determine the adjustment amount of the liquid distributor according to the target superheat degree of exhaust and the current superheat degree of exhaust" further includes: If the current superheat degree of exhaust is within the range of the target superheat degree of exhaust ± superheat degree of exhaust dead zone, then the adjustment amount = 0.

5. The control method of the air conditioning system according to claim 3, characterized in that, "Determine the adjustment amount of the liquid distributor according to the target superheat degree of exhaust and the current superheat degree of exhaust" further includes: When the absolute value of the single adjustment amount δU(K) is greater than the single maximum allowable adjustment amount, the liquid distributor is adjusted according to the single maximum allowable adjustment amount.

6. The control method of the air conditioning system according to claim 1, characterized in that, "Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" includes: Determine the target liquid level of the evaporator according to the target operating parameters of the air conditioning system; Determine the current liquid level of the evaporator according to the actual operating parameters of the air conditioning system; Determine the adjustment amount of the liquid distributor according to the target liquid level and the current liquid level.

7. The control method of the air conditioning system according to claim 1, characterized in that "Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" includes: Determine the target water temperature difference liquid level between the inlet and outlet of the evaporator according to the target operating parameters of the air conditioning system; Determine the current water temperature difference between the inlet and outlet of the evaporator according to the actual operating parameters of the air conditioning system; Determine the adjustment amount of the liquid distributor according to the target water temperature difference between the inlet and outlet and the current water temperature difference between the inlet and outlet.

8. The control method of the air conditioning system according to claim 1, characterized in that "Determine the opening degree of the liquid distributor according to the operating parameters of the air conditioning system" includes: Determine the target pressure difference between the condenser and the evaporator according to the target operating parameters of the air conditioning system; Determine the actual pressure difference between the condenser and the evaporator according to the actual operating parameters of the air conditioning system; Determine the adjustment amount of the liquid distributor according to the target pressure difference and the current pressure difference.

9. An air conditioning system, characterized in that, It includes a liquid distributor and a control module, and the control module is configured to be able to execute the control method of the air conditioning system as described in any one of claims 1 - 8.

10. The air-conditioning system according to claim 9, characterized in that, The liquid distributor includes a substrate (1), an adjustment plate (2) and a driving member; A plurality of first liquid distribution holes (11) are provided on the substrate (1). The adjusting plate (2) is attached to and slidably arranged on the substrate (1). The driving member can drive the adjusting plate (2) to move so as to adjust the area covered by the first liquid distribution holes (11), and further adjust the passing area of the first liquid distribution holes (11); and / or Second liquid distribution holes (21) corresponding to the first liquid distribution holes (11) are provided on the adjusting plate (2); and / or One of the adjusting plate (2) and the substrate (1) is provided with a connecting post (12), and the other is provided with a sliding groove (22). The connecting post (12) is arranged through the sliding groove (22).

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